It may be advantageous in the UV irradiation of surfaces, in particular sterilization, if flushing of the spatial area between the emitter and the surface using a flushing gas is performed at least during the irradiation, possibly also prior to and/or after said irradiation. This is intended to remove gases absorbing UV radiation between the surface to be irradiated and the UV emitter at least during the irradiation. A suitable flushing gas is in particular nitrogen or noble gases. A defined atmosphere between the emitter and the surface and consequently the use of a suitable process gas can be advantageous even in other irradiation processes. The term process gas is used in the text which follows as a generic term for one or more suitable gases for flushing or for other processes prior to, during and/or after the irradiation.
For the irradiation of easily accessible surfaces, for example flat films, the flushing gas has until now been supplied around the emitter or from the side by means of a separate device. Disadvantages here are the additional complexity involved in terms of apparatus and the necessary adaptation of the flushing arrangement and the emitter with respect to one another. In addition, these systems can generally not be used within cavities with narrow access openings such as canisters or bottles for reasons of space.
Document EP 1 506 567 B1 discloses a UV emitter on the basis of a single-sided dielectric barrier discharge. For this purpose, the discharge vessel 2 is filled with xenon. During the gas discharge, which is preferably operated by means of a pulsed operating method described in U.S. Pat. No. 5,604,410, so-called excimers are formed. Excimers are excited molecules, for example Xe2*, which emit electromagnetic radiation on reversal to the generally unbounded basic state. In the case of Xe2*, the maximum of the molecular band radiation is approximately 172 nm. In order to produce the dielectric barrier discharge, a first filament-like electrode 23 is arranged coaxially within the tubular discharge vessel 2. Six strip-shaped outer electrodes 8a-8f are arranged in parallel with one another and spaced apart from one another on the outer side of the discharge vessel 2.
Document EP 0 607 960 A1 discloses a tubular UV emitter on the basis of a two-sided dielectric barrier discharge. The emitter vessel is in the form of a coaxial double tube arrangement, in which an inner tube and an outer tube are connected to one another in gas-tight fashion at both end sides. The discharge space surrounded by the discharge vessel extends between the inner tube and the outer tube in this arrangement.
Document EP 1 232 518 B1 discloses a flat discharge lamp on the basis of a two-sided dielectric barrier discharge. The dielectric barrier discharge is produced between a bottom plate and a cover plate, wherein the surrounding sealing frame and funnel-shaped supporting elements are integrated in the cover plate. The electrodes are fitted as two mutually meshing comb-like line structures on the outer side of the bottom plate.